Health and Human Services Secretary Alex Azar says the U.S. has signed a contract with Pfizer for delivery in December of the first 100 million doses of a COVID-19 vaccine the pharmaceutical company is working to develop.

He says the U.S. could buy another 500 million doses under the agreement.

Pfizer Inc. and BioNTech SE announced separately that the agreement is with HHS and the Defense Department for a vaccine candidate the companies are developing. It's part of President Donald Trump’s Operation Warp Speed program, under which multiple COVID-19 vaccines are being developed simultaneously.

The program aims to deliver 300 million doses of a safe and effective COVID-19 vaccine by January 2021. 

Copyright 2020 Health News Florida. To see more, visit .